Background: Bacteremia and candidaemia are important causes of mortality in the hospital. Rapid identification of pathogens and resistance genes from positive blood cultures (PBCs) can help in the early selection of appropriate antimicrobial therapy. The Investigation-Use-Only (IUO) BIOFIRE® Blood Culture Identification 2 (BCID2) Panel (BIOFIRE, Salt Lake City, UT) simultaneously detects 33 pathogens and 10 resistance genes in approximately one hour. The performance of the BCID2 Panel during a prospective evaluation study is compared to standard of care (SoC), as well as to independent PCR comparator assay (compPCR) results.
Materials/methods: Eighty-four aerobic and anaerobic de-identified PBCs from 84 patients with at least one gram-negative bacterium or fungus detected by Gram stain were tested using the BCID2 Panel. SoC included culture, standard biochemical identification and antimicrobial susceptibility testing (AST) of pathogens. Aliquots of residual PBCs and isolates were frozen for compPCR testing and discrepancy resolution. Sensitivity/positive percent agreement (PPA) and specificity/negative percent agreement (NPA) were determined for each BCID2 Panel analyte as compared to SoC.
Results: The BIOFIRE® Blood Culture Identification 2 (BCID2) Panel results matched SoC results in 162/171 detections. The nine results that were initially categorized as false-positives were favorably resolved by compPCR as true-positives. Sensitivity/PPA and specificity/NPA of the BCID2 Panel with SoC identification methods were 97.9% and 99.8%, respectively. Twelve out of 13 Candida were identified by the BCID2 Panel (5 Candida albicans, 4 Candida parapsilosis, 2 Candida krusei, 1 Candida tropicalis) while only 1 case of Candida lusitaniae remained unidentified since it is not included in the panel’s analytes. Six Enterobacterales species that exhibited resistance to 3rd generation cephalosporins by SoC, were correctly detected as CTX-M positive by the BCID2 Panel. Furthermore, eight Enterobacterales species resistant to carbapenems tested positive for carbapenemase genes (4 KPC, 3 VIM, 1 NDM) by the BCID2 Panel.
Conclusions: The BCID2 Panel with its new expanded menu has exhibited high sensitivity and specificity for pathogen identification. Consequently, the BIOFIRE® Blood Culture Identification 2 (BCID2) Panel is expected to provide rapid and accurate results for key pathogens, as well as important antimicrobial resistance genes.
Data presented are from assays that have not been cleared or approved for diagnostic use.